1. Field of the Invention (Technical Field)
The present invention relates to a composite material derived from agricultural products and agricultural by-products that can be formed or molded into various shapes.
2. Background Art
Much effort has been expended in the effort to develop an inexpensive material that has a low or positive impact on the environment, and can be used for forming various articles for industrial and consumer use. To date, none of these efforts has been entirely satisfactory.
For example, U.S. Pat. No. 5,344,871, to Timm et al., teaches the use of naturally occurring binders derived from certain agricultural products, such as proteins from cereal grasses, leguminous plants, or from leaves. Grains that have had the starch removed in the process of forming alcohol or defatted corn germ may also be used to make an organic binder. High temperatures and pressures are applied for a sufficient time to alter or denature the molecular structure of the protein resulting in polymerization. The shaping or molding process requires no chemical additives but it is useful to include sufficient amounts of water to increase heat transfer and to render the protein sufficiently flexible to flow around the materials to be bound.
U.S. Pat. No. 4,306,059, to Yokobayashi et al., teaches the use of a specific alphaglucan, termed Elsinan. Elsinan is a sugar comprised of repeating units of D-glucopyranose. An advantage of using Elsinan over other sugars, such as amylose, is that the formed products are moisture and water resistant, transparent, and storable for long periods of time without losing their desirable properties. Fillers can be mixed with the Elsinan in the range of 10,000 to 0.0001, respectively, based on dry weight. A similar sugar, Pullalan, has been used in combination with water soluble materials, such as starch, gelatin, or casein to bind chemical fertilizers in a form more suitable for application. U.S. Pat. No. 4,045,204, to Matsunaga et al.
The present invention is of a composite mixture comprising an organic powder, starch, and a liquid. In the preferred embodiment, the composite mixture comprises approximately one part organic powder of particle size less than or equal to approximately 1 mm, one part starch, and two parts liquid, preferably water. The composite mixture of may also comprise fibrous organic material when an increase in strength of the inventive material is desired. The organic powder may comprise any powdered crop cuttings, but preferably straw powder.
The invention is further of a method of making a formed product from the inventive composite mixture comprising the steps of: combining an organic powder, starch and a liquid to form a slurry; pressing the slurry into a mold; heating the mold; and removing the formed product from the mold. In the preferred embodiment, the composite mixture comprises approximately one part organic powder of particle size less than or equal to approximately 1 mm, one part starch, and two parts liquid, preferably water. The composite mixture may also comprise fibrous organic material when an, increase in strength of the inventive material is desired. Once all the above materials are combined to form a slurry, the slurry is pressed into a mold and heated to an appropriate temperature, preferably at or above approximately 300xc2x0 F. The organic powder may comprise any powdered crop cuttings, but preferably straw powder. After the removal of the molded product comprised of the inventive composite mixture, the molded product can.be optionally formed into a laminated structure, coated or both finishing processes may be applied. The formed product can be utilized as any disposable item for consumer use, preferably a food container.
The present invention is also of a molded product comprising an organic powder, starch, and a liquid. In the preferred embodiment, the particle size of the organic powder is less than or equal to approximately 1 mm, and the composite mixture comprises approximately one part organic powder, one part starch, and two parts liquid, preferably water.
A primary object of the present invention is to provide an inexpensive, biodegradable composite mixture that is easily shaped into various formed products. After consumption, the resulting formed products provide a positive environmental benefit compared with materials presently being utilized for similar industrial and consumer uses.
A primary advantage of the present invention is that it is comprised of relatively inexpensive and easily renewable materials.
An additional advantage of the present invention is the positive benefit it provides to the natural environment compared with other materials used for similar purposes.
Another advantage of the present invention is its ability to be molded into a rigid form. The rigid form allows for a consistent and predictable shape. Further, the strength of the resulting formed products can be adjusted to support a given load by varying the composition of the inventive composite mixture.
Still another advantage of the present invention is its heat insulation properties, its electrical insulation properties, its acoustical dampening properties, as well as its ability to hold a rigid form for an extended period.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.